JP3217210B2 - Manufacturing method of liquid crystal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal display device such as an active matrix type liquid crystal display or a projection type projector using an active matrix type light valve.

[0002]

2. Description of the Related Art FIG. 12 is a sectional view of one pixel of an array substrate provided with a conventional signal holding capacitor and a thin film transistor. 12, reference numeral 1 denotes an insulating substrate, 2 denotes a silicon thin film formed on the insulating substrate 1 and functions as a channel, 3 denotes a gate insulating film formed on the silicon thin film 2, and 4 denotes a gate insulating film. 5, a source / drain region in which the silicon thin film is doped with impurities such as phosphorus and boron at a high concentration, a channel region 6 made of the silicon thin film 2, and a whole surface on the insulating substrate 1. , A signal holding capacitor electrode formed on the first interlayer insulating film, a second interlayer insulating film covering the signal holding capacitor electrode, and a second interlayer insulating film covering the signal holding capacitor electrode A pixel electrode formed on the layer 9, a third interlayer insulating film layer 11 covering the pixel electrode 10, and a first contact hole 12 formed in the third interlayer insulating film. Second contact holes 13 are formed in the gate insulating film 3 and the first interlayer insulating film 7, and a source electrode 14 and a drain electrode 15 made of metal are connected to the source / drain regions 5.

A thin film transistor is composed of the source / drain region 5, channel region 6, gate insulating film 3 and gate electrode 4 shown in FIG. A signal storage capacitor is composed of the signal storage capacitor electrode 8, the pixel electrode 10, and the second interlayer insulating film layer 9 of FIG.

FIGS. 10 and 11 are cross-sectional views of a manufacturing process for explaining a manufacturing process of the liquid crystal display device shown in FIG.

First, as shown in FIG. 10A, after a silicon thin film 2 serving as a channel of a thin film transistor is formed on an insulating substrate 1, a gate insulating film 3 made of a silicon oxide film is formed by, for example, a thermal oxidation method or a CVD method. It is formed by a method.

Next, as shown in FIG. 10B, a doped silicon thin film to which phosphorus is added, for example, is formed on the gate insulating film 3 by a method such as low-pressure CVD. Is patterned to form a gate electrode 4. Then, using the gate electrode 4 as a mask, for example, phosphorus is ion-implanted into the silicon thin film 2 to form a source / drain region 5 and a channel region 6 in the silicon thin film 2. . If the thickness of the channel region 6 is too small, the ON current decreases. If the thickness is too large, the OFF current increases due to the light leakage current.
It is preferable to set the angle to 0 to 1000 °.

Next, as shown in FIG. 10C, a first interlayer insulating film 7 made of a silicon oxide film is
It is formed by a method.

Next, as shown in FIG. 10D, for example, an ITO thin film is formed on the first interlayer insulating film 7 by a sputtering method or a CVD method, and the ITO thin film is patterned. The signal holding capacitance electrode 8 is formed.

Next, as shown in FIG. 11E, for example, after a silicon nitride film is formed by a method such as plasma CVD to form a second interlayer insulating film layer 9, a silicon thin film 2 serving as a channel is formed. The upper silicon nitride film is patterned and removed.

Next, as shown in FIG.
For example, an ITO thin film is formed on the interlayer insulating film layer 9 by a sputtering method or a CVD method, and the pixel electrode 10 is formed by patterning the ITO thin film.

Next, as shown in FIG. 11 (g), for example, after a silicon nitride film is formed by a method such as plasma CVD to form a third interlayer insulating film layer 11, a silicon thin film 2 serving as a channel is formed. The upper silicon nitride film is patterned and removed, and at the same time, a first contact hole 12 is formed.

Next, the second gate insulating film 3 and the first interlayer insulating film layer 7 on the source / drain region 5
After forming the contact hole 13, a metal thin film is formed and patterned inside and outside the contact hole to form a source electrode 14 and a drain electrode 15, and a signal holding capacitor having two electrodes as shown in FIG. Is manufactured.

In the manufacturing process shown in FIGS. 10 to 11 for obtaining the conventional pixel shown in FIG. 12, the number of steps is large, and defects are likely to occur.

As a method of simplifying the above-described manufacturing process, as described in Japanese Patent Application Laid-Open No. 1-129234, a signal holding capacitor electrode is formed in the same manner as a channel when forming a channel portion of a thin film transistor. There has been proposed a method of forming a material by using the same manufacturing process.

According to the method of simultaneously forming the signal holding capacitor electrode and the channel portion of the thin film transistor with the same material for simplifying the manufacturing process, the signal holding capacitor electrode is thinned to a thickness through which visible light can be transmitted, for example, 200 ° or less. thing,
When the thickness of the channel portion becomes insufficient, on-current is reduced, and the display quality of a liquid crystal display device using the thin film transistor array is reduced. Conversely, if the channel portion is thickened to, for example, 300 ° or more so that a sufficient ON current can be obtained, the signal storage capacitor electrode portion becomes difficult to transmit visible light, and the displayed image becomes dark.

[0016]

SUMMARY OF THE INVENTION The present invention simplifies the manufacturing process without deteriorating the display quality by solving the problem that the conventional manufacturing method has such a large number of steps that defects are likely to occur. That is what we are trying to solve.

[0017]

According to a first aspect of the present invention, there is provided an array substrate in which a plurality of display electrodes each having a thin film transistor and a signal holding capacitor are arranged in a matrix at intersections between address lines and data lines. When,
In the process of manufacturing a liquid crystal display device in which a liquid crystal layer is sandwiched between an opposing substrate on which a transparent electrode is formed, a signal holding capacitor electrode and a channel portion of a thin film transistor are simultaneously formed and patterned with the same semiconductor material. And then form the gate electrode
The present invention relates to a method of manufacturing a liquid crystal display device, characterized in that the thickness of a signal holding capacitor electrode is reduced as a mask for a liquid crystal part.

According to a second aspect of the present invention, as a method of reducing the thickness of the signal storage capacitor electrode as compared with the thickness of the channel portion of the thin film transistor, the channel portion is made to have a structure that is not oxidized or hardly oxidized. Preferably, both the channel portion and the signal storage capacitor electrode are annealed in an oxidizing atmosphere. Also for annealing
Alternatively, an etching process may be performed.

In the third aspect of the present invention, it is preferable that impurities are added to the source region, the drain region and the signal storage capacitor electrode after the annealing in the oxidizing atmosphere.

In the fourth aspect of the present invention, it is preferable that the annealing in the oxidizing atmosphere is performed after forming an interlayer insulating film made of an oxide insulating film.

In the fifth aspect of the present invention, the annealing in the oxidizing atmosphere is preferably performed at 900 ° C. or less.

In the sixth aspect of the present invention, the annealing in the oxidizing atmosphere is preferably performed at 2 atm or more.

In the seventh aspect of the present invention, it is preferable that the annealing in the oxidizing atmosphere is performed while supplying lead atoms.

[0024]

Operation and Embodiment An embodiment of the first invention in the present invention will be described. 1 and 2 are sectional views showing the manufacturing process of the first invention. As shown in FIG. 1A, first, a silicon thin film 2 serving as a channel of a thin film transistor and a signal holding capacitor electrode 8 are formed on an insulating substrate 1.
Is formed of a semiconductor material by film formation and patterning by, for example, a CVD method, and then a gate insulating film 3 made of, for example, a silicon oxide film is formed by, for example, a thermal oxidation method or a CVD method. At this time, the thickness of the channel is set so as to be sufficient to allow the on-current required for the thin film transistor to flow, for example, 600 °.

Examples of the semiconductor material include polycrystalline silicon and amorphous silicon, and polycrystalline silicon is preferable in that a transistor having high mobility can be obtained.

Next, as shown in FIG. 1 (b), a polycrystal doped with, for example, phosphorus is formed on the portion of the gate insulating film 3 where a channel region is to be formed, by film forming and patterning using a low pressure CVD method or the like. A gate electrode 4 made of a silicon material is formed. Thereafter, the region of the silicon thin film 2 where the gate electrode 4 is not located above and the gate insulating film 3 which is located above the region of the signal holding capacitor electrode 8 are etched. Is etched until the thickness becomes sufficiently permeable, for example, about 200 °. According to the first aspect, the process of forming the signal holding capacitor electrode can be simplified, and the thickness of the signal holding capacitor electrode portion and the channel portion can be set independently, so that the signal holding capacitor electrode portion transmits visible light. The film thickness can be set to a possible film thickness, and the channel portion can be set to a film thickness at which an on-current sufficient for display can be obtained. The portion covered with the gate electrode 4 in the silicon thin film 2
Since the film is not etched, the film thickness remains at the initial film thickness.

Next, as shown in FIG. 1C, for example, phosphorus is ion-implanted into the silicon thin film 2 and the signal storage capacitor electrode 8 using the gate electrode 4 as a mask. In this manner, the source / drain region 5 and the channel region 6 are formed in the silicon thin film 2 and the resistance of the signal holding capacitor electrode 8 is reduced. The same structure can be obtained even if the order of the etching of the gate insulating film 3 and the signal holding capacitor electrode 8 and the ion implantation are changed.

Next, as shown in FIG. 1D, a first layer made of, for example, a silicon oxide film or a silicon nitride film is formed.
The interlayer insulating film 7 is formed by, for example, a CVD method. This first
The interlayer insulating film 7 becomes a capacitive insulating film in the signal holding capacitor portion.

Next, as shown in FIG. 2E, for example, an ITO thin film is formed on the first interlayer insulating film 7 by a sputtering method or the like, and the ITO thin film is patterned to form a pixel electrode 10. To form

Next, as shown in FIG. 2F, for example, a silicon silicon nitride film is formed by, for example, a CVD method, and the nitride film on the silicon thin film 2 serving as a channel is patterned and removed. By forming the holes 12, the third interlayer insulating film layer 11 is formed.

Next, after a second contact hole 13 is formed in the first interlayer insulating film 7 above the source / drain region 5, a metal thin film is formed inside and outside the first contact hole 12 and the second contact hole 13. And drain electrode 1 and drain electrode 1
5, and the liquid crystal display device shown in FIG. 2 (g) is manufactured.

An embodiment of the second invention in the present invention will be described. 3 and 4 are sectional views showing the manufacturing process of the second invention. As shown in FIG.
First, a silicon thin film 2 serving as a channel of a thin film transistor and a signal holding capacitor electrode 8 are formed on a insulating substrate 1 from a polycrystalline silicon material by, for example, film formation and patterning by a CVD method, and then a gate made of, for example, a silicon oxide film is formed. The insulating film 3 is formed by, for example, a thermal oxidation method. At this time, the thickness of the channel is set so as to be sufficient to allow sufficient on-current required for the thin film transistor, for example, 600 °.

Next, as shown in FIG. 3 (b), a polycrystalline film doped with, for example, phosphorus is formed on the portion of the gate insulating film 3 where a channel region is to be formed by film formation and patterning by a low pressure CVD method or the like. A gate electrode 4 made of a silicon material is formed. Using the gate electrode 4 as a mask, the channel portion has a structure that is not oxidized or hardly oxidized, and phosphorus is ion-implanted into the silicon thin film 2 to form a source / drain region 5 and a channel region 6 in the silicon thin film 2. . At this time, ions are simultaneously implanted into the signal holding capacitor electrode 8.

Thereafter, as shown in FIG. 3C, an oxidizing atmosphere, for example, O 2, is used until the thickness of the signal storage capacitor electrode 8 becomes sufficiently thick to transmit visible light, for example, about 200 °.
_2. Annealing is performed in an atmosphere such as water vapor, N ₂ O, CO _{2, or} a mixed gas of these gases. According to the second aspect, when the thickness of the signal storage capacitor electrode is reduced in the manufacturing method of the first aspect, the film thickness can be accurately controlled. At this time, since the channel portion is under the gate electrode pattern, it is not thermally oxidized and the film thickness does not change.

Next, as shown in FIG. 3D, a first interlayer insulating film 7 made of, for example, a silicon oxide film or a silicon nitride film is formed by, for example, a CVD method. The capacitance insulating film of the signal holding capacitor portion is a three-layer film of an insulating film in which the first interlayer insulating film 7, the gate insulating film 3, and the signal holding capacitor electrode 8 are thermally oxidized.

Next, as shown in FIG. 4E, for example, an ITO thin film is formed on the first interlayer insulating film 7 by a sputtering method or the like, and the pixel electrode is formed by patterning the ITO thin film. Form 10.

Next, as shown in FIG. 4F, for example, a silicon nitride film is formed by, eg, CVD, and the nitride film on the silicon thin film 2 serving as a channel is patterned and removed, and at the same time, the first contact hole is formed. 12, the third interlayer insulating film 11 is formed.

Next, after forming a second contact hole 13 in the first interlayer insulating film 7 on the source / drain region 5, the first contact hole 12 and the second contact hole 13 are formed.
A thin metal film is formed inside and outside the contact hole 13 and patterned to form a source electrode 14 and a drain electrode 15.
Is formed, and the liquid crystal display device shown in FIG.

FIG. 5 is a sectional view of a thin film transistor array manufactured by the manufacturing method of the second invention in the present invention. In the second invention, the first interlayer insulating film 7 is omitted, and the third interlayer insulating film layer 11 on the silicon thin film 2 serving as a channel is left. In this case, the capacitor insulating film of the signal holding capacitor portion has a two-layer structure of the gate insulating film 4 and the insulating film in which the signal holding capacitor electrode 8 is thermally oxidized. According to this method, the same effect as when the first interlayer insulating film 7 is provided can be obtained.

An embodiment of the third invention according to the present invention will be described. 6 and 7 are sectional views showing the manufacturing steps of the third invention. As shown in FIG.
First, a silicon thin film 2 serving as a channel of a thin film transistor and a signal holding capacitor electrode 8 are formed on a insulating substrate 1 using a polycrystalline silicon material by film formation and patterning, for example, by a CVD method, and then a gate made of, for example, a silicon oxide film is formed. The insulating film 3 is formed by, for example, a thermal oxidation method. At this time, the thickness of the channel is set so as to be sufficient to allow the on-current required for the thin film transistor to flow, for example, 600 °.

Next, as shown in FIG. 6B, a polycrystal doped with, for example, phosphorus is formed on the portion of the gate insulating film 3 where a channel region is to be formed by film formation and patterning by a low pressure CVD method or the like. A gate electrode 4 made of a silicon material is formed.

Next, as shown in FIG. 6C, an oxidizing atmosphere, for example, O 2, is used until the thickness of the signal storage capacitor electrode 8 becomes sufficiently thick to transmit visible light, for example, about 200 °.
_2. Annealing is performed by thermal oxidation in an atmosphere of water vapor, CO _2, and a mixed gas of these gases. At this time,
Since the channel portion is under the gate electrode pattern, it is not thermally oxidized and the film thickness does not change.

Next, as shown in FIG. 6D, using the gate electrode 4 as a mask, an impurity is added to the silicon thin film 2 to form a source / drain region 5 and a channel region 6 in the silicon thin film 2. . At this time, an impurity is also added to the signal holding capacitor electrode 8 at the same time. Examples of the impurities include P, As, B, Sb, Bi, etc., but P and B are preferable from the viewpoint of easy implantation.

According to the third aspect, during the annealing treatment in the oxidizing atmosphere according to the second aspect, the additional impurities can be prevented from diffusing from the source region and the drain region to the outside.

Next, as shown in FIG. 7E, a first interlayer insulating film 7 made of, for example, a silicon oxide film or a silicon nitride film is formed by, for example, a CVD method or a sputtering method. The signal holding capacitance electrode 8 becomes a three-layered film of the thermally oxidized insulating film.

Next, as shown in FIG. 7F, for example, an ITO thin film is formed on the first interlayer insulating film 7 by sputtering or the like, and the ITO thin film is patterned to form the pixel electrode 10. Form.

Next, as shown in FIG. 7G, a third interlayer insulating film layer 11 is formed by, for example, forming a silicon nitride film by, for example, a CVD method, and then nitriding on the silicon thin film 2 serving as a channel. The film is patterned and removed, and a first contact hole 12 is formed at the same time.

Next, after a second contact hole 13 is formed in the first interlayer insulating film 7 above the source / drain region 5, a metal thin film is formed inside and outside the first contact hole 12 and the second contact hole 13. Are formed and patterned to form the source electrode 14 and the drain electrode 15, and the liquid crystal display device shown in FIG. 7H is manufactured.

An embodiment of the fourth invention of the present invention will be described. 8 and 9 are sectional views showing the manufacturing method of the fourth invention. As shown in FIG.
First, a silicon thin film 2 serving as a channel of a thin film transistor and a signal holding capacitor electrode 8 are formed on a insulating substrate 1 from a polycrystalline silicon material by, for example, film formation and patterning by a CVD method, and then a gate made of, for example, a silicon oxide film is formed. The insulating film 3 is formed by, for example, a thermal oxidation method. At this time, the thickness of the channel is set so as to be sufficient to allow sufficient on-current required for the thin film transistor, for example, 600 °.

Next, as shown in FIG. 8B, a polycrystalline film to which, for example, phosphorus is added by means of film formation by a low pressure CVD method or the like and patterning on the portion of the gate insulating film 3 where a channel region is to be formed. A gate electrode 4 made of a silicon material is formed. Using the gate electrode 4 as a mask, the silicon thin film 2 is ion-implanted with phosphorus into the silicon thin film 2.
Then, a source / drain basin 5 and a channel region 6 are formed. At this time, ions are simultaneously implanted into the signal holding capacitor electrode 8.

Next, as shown in FIG. 8C, a first interlayer insulating film 7 made of an oxide insulating film is formed by, for example, a CVD method or a sputtering method. As the oxide insulating film,
For example, SiO ₂ , Al ₂ O ₃ , phosphorus glass and the like can be mentioned, but an SiO ₂ film is preferable because it is oxidized later and has no impurities in the film and can be easily formed.

Thereafter, as shown in FIG. 8D, an oxidizing atmosphere, for example, O 2, is used until the thickness of the signal storage capacitor electrode 8 becomes sufficiently thick to transmit visible light, for example, about 200 °.
_2. Annealing is performed by thermal oxidation in an atmosphere of water vapor, N ₂ O, CO _2, and a mixed gas of these gases. At this time, since the channel portion is under the patterning of the gate electrode, it is not thermally oxidized and the film thickness does not change. According to the fourth aspect, the effect of the second aspect is obtained, and at the same time, the quality of the protective film is improved by annealing in an oxidizing atmosphere, and the source region, the drain region, and the signal storage capacitor electrode portion are improved. Since the activation treatment of the implanted additional impurities can be performed at the same time, the number of annealing steps is not increased. The capacitance insulating film of the signal holding capacitor portion is a three-layer film of the first interlayer insulating film 7, the gate insulating film 3, and the insulating film in which the signal holding capacitor electrode 8 is thermally oxidized.

Next, as shown in FIG. 9E, for example, an ITO thin film is formed on the first interlayer insulating film 7 by sputtering or the like, and the ITO thin film is patterned to form the pixel electrode 10. Form.

Next, as shown in FIG. 9F, for example, a silicon nitride film is formed by, for example, a CVD method to form a third interlayer insulating film layer 11, and then nitrided on the silicon thin film 2 serving as a channel. The film is patterned and removed, and a first contact hole 12 is formed at the same time.

Next, after a second contact hole 13 is formed in the first interlayer insulating film 7 above the source / drain region 5, a metal thin film is formed inside and outside the first contact hole 12 and the second contact hole 13. Is formed and patterned to form the source electrode 14 and the drain electrode 15, and the liquid crystal display device shown in FIG. 9G is manufactured.

As a fifth embodiment of the present invention, the step of thermally oxidizing and annealing for reducing the thickness of the signal holding capacitor in each of the second to fourth embodiments of the present invention is described below.
For example, it is performed at 900 ° C.

According to the fifth aspect, by performing the annealing process in an oxidizing atmosphere at a low temperature, it is possible to prevent the additional impurities from diffusing to the outside from the source region and the drain region, and further from the inside of the gate electrode.

As a sixth embodiment of the present invention, the step of thermally oxidizing and annealing for thinning the signal storage capacitor electrode 8 of each of the second to fifth embodiments of the present invention may be performed, for example, using steam. Medium, at 50 atm.

According to the sixth aspect, the growth rate of the oxide film is increased, and the annealing time in an oxidizing atmosphere can be shortened.

As a seventh embodiment of the present invention, the step of thermally oxidizing and annealing for reducing the thickness of the signal storage capacitor electrode 8 in each of the second to fifth embodiments of the present invention is, for example, lead. Performed with lead oxide powder as a source of atoms.

According to the seventh aspect of the invention, the growth rate of the oxide film is increased by mixing lead atoms into the oxide film, and the annealing time in an oxidizing atmosphere can be shortened.

[0062]

According to the first aspect of the present invention, the step of forming the signal holding capacitor electrode can be simplified, the yield can be improved, and at the same time, the signal holding capacitor electrode portion and the channel portion can be simultaneously formed of the same semiconductor material. The thickness of the signal storage capacitor electrode can be set to a thickness that allows visible light to pass therethrough, while the thickness of the channel portion can be set to a thickness that allows sufficient on-current for display. , Display quality is not degraded.

According to the second aspect of the present invention, when the thickness of the signal storage capacitor electrode is reduced in the first aspect, the film thickness can be accurately controlled, and the distribution of visible light transmission is reduced. it can.

According to the third aspect of the present invention, it is possible to prevent the additional impurities from diffusing to the outside from the source region and the drain region during the annealing process in the oxidizing atmosphere in the second aspect. In addition, the influence on the characteristics of the manufactured thin film transistor can be reduced.

According to the fourth aspect of the present invention, the effect of the second aspect is obtained, and at the same time, the film quality of the protective film is improved by annealing in an oxidizing atmosphere. Since the activation process of the impurity added to the capacitor electrode can be performed at the same time, the annealing process is not increased.

According to the fifth aspect of the present invention, the annealing treatment in the oxidizing atmosphere according to the second to fourth aspects of the present invention is performed at a low temperature so that the source and drain regions,
Further, the additional impurity can be prevented from diffusing to the outside from the inside of the gate electrode, and the influence on the characteristics of the manufactured thin film transistor can be reduced.

According to the sixth aspect of the present invention, the growth rate of the oxide film is increased, and the annealing time in an oxidizing atmosphere can be reduced.

According to the seventh aspect of the present invention, the growth rate of the oxide film is increased by the penetration of lead atoms into the oxide film, and the annealing time in an oxidizing atmosphere can be shortened.

[Brief description of the drawings]

FIG. 1 is a method for manufacturing a liquid crystal display according to an embodiment of the first invention in the present invention.

FIG. 2 is a method for manufacturing a liquid crystal display according to an embodiment of the first invention in the present invention.

FIG. 3 is a method for manufacturing a liquid crystal display according to an embodiment of the second invention.

FIG. 4 is a method for manufacturing a liquid crystal display according to an embodiment of the second invention.

FIG. 5 is a sectional view showing a liquid crystal display device according to an embodiment of the second invention in the present invention.

FIG. 6 is a method for manufacturing a liquid crystal display according to an embodiment of the third invention in the present invention.

FIG. 7 is a method for manufacturing a liquid crystal display according to an embodiment of the third invention in the present invention.

FIG. 8 is a method for manufacturing a liquid crystal display according to an embodiment of the fourth invention in the present invention.

FIG. 9 is a method for manufacturing a liquid crystal display according to an embodiment of the fourth invention in the present invention.

FIG. 10 shows a conventional method for manufacturing a liquid crystal display device.

FIG. 11 shows a method for manufacturing a conventional liquid crystal display device.

FIG. 12 is a cross-sectional view illustrating a conventional liquid crystal display device.

[Explanation of symbols]

1 Insulating substrate, 2 silicon thin film to be a channel, 3
Gate insulating film, 4 gate electrodes, 5 source / drain regions, 6 channel regions, 7 first interlayer insulating film, 8 signal storage capacitor electrode, 9 second interlayer insulating film layer, 10 pixel electrode, 11 third interlayer insulating film layer , 12 first contact hole, 13 second contact hole, 14 source electrode, 15 drain electrode.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/1368 G02F 1/1343

Claims (8)

(57) [Claims] A plurality of display electrodes each having a thin film transistor and a signal storage capacitor are arranged between an array substrate in which a plurality of display electrodes are arranged in a matrix at intersections of address lines and data lines, and a counter substrate on which transparent electrodes are formed. In a manufacturing process of a liquid crystal display device constituted by sandwiching a liquid crystal layer, a signal storage capacitor electrode and a channel portion of a thin film transistor are formed by simultaneously forming and patterning a film with the same semiconductor material, and then a gate electrode formed
A method for manufacturing a liquid crystal display device, wherein the thickness of the signal holding capacitor electrode is reduced using the mask of the channel portion as a mask . 2. As a method for reducing the thickness of the signal storage capacitor electrode of the thin film transistor, a method of manufacturing a liquid crystal display device according to claim 1, wherein the annealing in oxidation atmosphere. 3. The signal holding capacity of the thin film transistor.
As a method of reducing the pole thickness, etching
2. The liquid crystal display device according to claim 1, wherein: 4. The method according to claim 2, further comprising adding impurities to the source region, the drain region, and the signal storage capacitor electrode after the annealing process in the oxidizing atmosphere. 5. An annealing treatment in an oxidizing atmosphere,
3. The method for manufacturing a liquid crystal display device according to claim 2, wherein the method is performed after forming an interlayer insulating film made of an oxide insulating film. 6. An annealing treatment in an oxidizing atmosphere is performed for 9 days.
00 ° C. claim 2, characterized in that to perform the following, 4 also
Is a method for manufacturing a liquid crystal display device according to item 5 . 7. An annealing treatment in the oxidizing atmosphere is performed by two
Claim 2, characterized in that to carry out the above pressure, 4, 5 or
7. The method for manufacturing a liquid crystal display device according to item 6 . 8. The method according to claim 2, wherein the annealing in the oxidizing atmosphere is performed while supplying lead atoms.
7. The method for manufacturing a liquid crystal display device according to 4 , 5, or 6 .